The present invention relates generally to medical devices and more particularly to a catheter for removing non-liquid material from a patient, such as a clot, thrombus or embolus from a vein.
One medical condition that affects a large number of patients is the formation of internal clots, thrombi and emboli within the vasculature. Some medical sources distinguish clots from thrombi and emboli. For example, a clot can be considered to be the initial stage of blood coagulation where blood forms a non-liquid mass due to reduced blood flow or other physiological conditions. A thrombus can be considered to be a more fibrous state of a clot where platelets and other cells aggregate to form a more solid mass. Oftentimes, a thrombus occurs where the collagen layer of a vessel becomes exposed since blood exposure to collagen encourages a cascade of clotting activity. However, numerous other factors can also encourage thrombus formation, such as hemodialysis grafts and certain drug treatments. A thrombus is generally considered to be a clotted mass that remains attached to a vessel wall, and is typically considered to be an embolus when the thrombus breaks loose from the vessel wall and flows through the vasculature. This can cause serious conditions because an embolus will often flow along the vasculature to a point where it obstructs downstream tissues, which can starve the obstructed tissues of blood and oxygen.
The seriousness of clotting formation and related events can vary from relatively minor conditions that are generally recoverable and/or treatable to life-threatening situations. For example, if the clotting involved is a short-term event and the individual is healthy, the vasculature may clear naturally without medical intervention. Hemodialysis patients with artificial fistulas may also suffer from thrombus formation within the fistula, which may require treatment or the surgical introduction of a new fistula. Deep vein thrombosis is another condition that can affect blood circulation within a patient's legs. This condition can start with mild symptoms of discomfort in the leg, but if left untreated thrombus formation can propagate throughout the patient's venous system and result in a life-threatening situation.
A number of methods for treating clots, thrombi and emboli have been tried. One method involves inserting a catheter so that the distal end of the catheter is close to the clot, thrombus or emboli. Suction is then applied to the lumen of the catheter to aspirate the vessel and suck the mass into the catheter and out of the vessel. However, the devices that are available for this treatment have various disadvantages. One concern is that any blood escaping from the catheter during use of the device should be minimized to reduce blood loss during the procedure. In addition, it can be difficult to remove non-liquid masses, like clots, thrombi and emboli, from conventional catheters that are not designed for this purpose.
Accordingly, the inventors believe that an improved catheter with a collection chamber for the removal of a non-liquid mass from a patient would be desirable.